Notices by Chip (bytex64@awesome.garden)

@botvolution Ah, maybe you’re thinking of the Xen or Xen-i, then. I don’t think they ever made a Xenix for the original PC/Xi.

@botvolution Twisted pair? I’m only familiar with serial networking on these.

Hey guys, it's April 1st. You know what that means!

No, not that.

It's #Aprilcot!!! The month-long celebration of Apricot computers (that's pretty much just me)!

If you're curious about the Apricot and what I got up to last year, I've made a dedicated site in the interim. https://bytex64.net/apricot/

But the short version is, the Apricot is a non-PC compatible DOS-based business computer from the UK. It's weird!

@thomasfuchs Storytelling. The ability to have other people internalize experience without being there is absolutely foundational to the evolution of humans as a social organism. (Though it’s so foundational one could argue we didn’t really invent it at all)

@botvolution Maybe you’re thinking of FairCamp (https://simonrepp.com/faircamp/) or Bandwagon (https://bandwagon.fm/), but those seem to be more focused on being bandcamp replacements.

I have acquired something very cool. A friend was buying some stuff on craigslist and the seller offered a discount on further items and forwarded some computer items to me. I got an ATX power supply and a fan, but I also spied THIS. A Triplett 630-NS Volt-Ohm-Milliammeter with the original manual and box!

It’s reportedly not working correctly, but assuming the gauge itself isn’t blown, I think I can fix it. Because this is from a time when tools were meant to be maintained. The manual has a full parts list and schematic.

I can’t find a date anywhere, but this manual is definitely older than the one you can find online. It does mention “special germanium diodes” to protect the movement from overloads, but that could still be late 40s. All the diagrams depict tubes.

Unfortunately the probes are knackered. I can rewire them, but the banana jack end is overmolded so it would have to be a splice job.

It has flat head screws holding it together, accessible down a very long narrow hole. Which means I do not have a screwdriver that can take this apart. :/

I suppose let’s start by testing it. The good news is the movement is fine. Voltage is working, though not very accurately. This should be dead on 5V.

The ohms range is non-functional, which I expected. That requires batteries, and I expect to see some alkaline horrors when I open this up.

The milliamps range is… weird. .12 and 1.2 seem to work properly through this 1 megohm resistor, but 12 and 120 are reading the same and very high, like those ranges are connected directly to the movement coil. 1200 is just dead. I’m guessing blown fuse.

The divide by two switch seems to work properly.

If anyone has an idea of when this is from, I’d love to hear it. This is the manual I found online, which clearly describes a newer version and uses their modern logo. https://chrisgrossman.com/manuals/triplett/Triplett_630NS.pdf

Some interesting differences:

- The old manual shows only tubes, coils, resistors, and capacitors in the example circuit diagrams. The new one shows transistors and diodes.
- The old manual has this kind of sketchy method for measuring capacitance, which is absent in the new one.
- The old manual refers to the batteries by Eveready part numbers, No. 950 and 915. The new manual refers to them as size D and AA.
- The old manual says the movement is protected by “germanium diodes”. In the new manual it’s a “silicon diode network”.

Testing this a little more, it seems like the .12, 1.2, and 1200mA ranges are measuring fine. That’s good news, as that most likely means there’s no fault in the movement itself.

DC volts is about 5-10% low, but AC is about 25% low.

This whole thing is made out of precision resistors. According to the parts list, most of them are metal film +/-0.5%, and three on the mA ranges are wire wound +/-0.25%. There’s a few carbon composition +/-5% but they’re not in critical locations. These are going to be annoyingly expensive.

Possibly the insulation on the wire wound ones has just gone, and some are shorted through. I wouldn’t expect the metal film ones to degrade but maybe the coatings were not that robust. I also wonder if this is all just a battery corrosion problem. 😬

I got a screwdriver and a good shop to recommend. This is a small local hardware store, one guy there. I ask for a narrow flat blade screwdriver and he shows me what they have on the rack. I find a 3/16” that looks it would work, but it has the usual trapezoidal head. I measure it and it’s almost exactly 1/4”, so I’m not sure it’ll fit.

“You could just grind that off,” he offers.

“Yeah, but I don’t have a grinder.”

“Oh, you can use ours.”

“Really!?”

“Yeah, sure.”

“Then I’ll take it!”

He rings me up, then leads me back to the grinder and lets me loose. Screwdriver worked great. :)

So if you need some tool help on the north side of Chicago, go to Andersonville Hardware. I’ll definitely be back.

@botvolution Funkwhale? https://www.funkwhale.audio/

Haven’t tried it myself and I have no idea if it fits the bill, but I recall people talking about it.

So I was tooling around in Windows 3.11 (as one does), and I noticed this in the list of built-in printers. "Apricot Laser". Turns out Apricot sold many rebadged printers. https://apricot-archive.co.uk/apricot-writer-printers

Hilariously, some of their laser printers were rebadged Apple LaserWriters!

Heck yeah, we're makin' some valentines.

@botvolution That’s unfortunate. The magic word here is “debootstrap”, but you’ll only know to search for that if you’re already quite familiar with the process.

(And in case you were still looking, this appears to be just about as manual as I could imagine. https://gist.github.com/subrezon/9c04d10635ebbfb737816c5196c8ca24)

The proto board will be lights and switches, and it connects via headers to a SparkFun ESP32 Thing. It turns out there’s just enough space between for a vape battery. I’ll design a case for it, but that’s a ways off yet.

I realized during planning that the 10 position bar graph display has the same 0.1 inch pitch as dupont headers, so that will be an indicator for signals on that port. You could show levels, activity, protocol detection, etc. I’m pretty pleased with that.

The fun part is this is a junk build. It’s all stuff I had lying around (… okay the LED modules I bought very recently more or less for this project but they’re lying around *now*).

So I’m making a… thing. A pocket tool sort of in the vein of a cyberdeck, but for low-medium speed digital signals analysis. Something you can use to poke at a circuit board in the field to figure out where the UART console is or the frequency of a clock or logging an I2C bus.